In my experience, the ratchet is seldom really bad and if it is, is not worth fixing, as any attempt to do so usually results in total ruination. a bit of welding on the hand or even making a new hand might be the better approach.

As to the grip, you can see in the picture the little "lips" that go under the sideplate. Many of those old revolvers, including the French 92 and the Russian Nagant work the same way, with the sideplate either removable or swinging out on a hinge.